Theoretical Study On Defect Structure And Photophysical Properties Of Graphene Quantum Dots

By processing graphene quantum dot,an ideal semiconductor material with suitable band gap and higher electron mobility can be obtained.Thus,it has a broad prospect in the application of photoelectric response materials.In this work,a graphene defect with porphyrin-like structure is selected to achieve the controllable light absorption.The double five-membered-ring parallel vacancy are based on self-healing properties of popular graphene defects.Aimed to separate exciton and hole more effectively and achieve higher photoelectric conversion efficiency,the occupied orbital and unoccupied orbital of the quantum dot with objected defect structure is taken as orderly dispersion to form an obvious charge separation state under the demonstration with first principles calculation.Most importantly,a real time real space charge separation is calculated by time-dependent ab-initio quantum dynamics based on numerical atomic basis sets.The result shows the specific graphene defects can form an efficient pure graphene photoelectric response medium like porphyrin skeleton,and the vacancy will induce to adjust and control the specific wavelength of the response light and manipulable charge separated state with parity layer of peripheral carbon rings by the accurate calculation of these ultrafast processes.